Lactation

Contraindications

Warnings/Precautions

Has not been established for use in initial episodes of genital herpes, patients with ophthalmic or disseminated zoster, or in immunocompromised patients with herpes zoster; dosage adjustment is required in patients with renal insufficiency (Clcr<60 mL/minute) and in patients with noncompensated hepatic disease; safety and efficacy have not been established in children <18 years of age; animal studies indicated increases in incidence of carcinomas, mutagenic changes, and decreases in fertility with extremely large doses

Ethanol/Nutrition/Herb Interactions

Mechanism of Action

After undergoing rapid biotransformation to the active compound, penciclovir, famciclovir is phosphorylated by viral thymidine kinase in HSV-1, HSV-2, and VZV-infected cells to a monophosphate form; this is then converted to penciclovir triphosphate and competes with deoxyguanosine triphosphate to inhibit HSV-2 polymerase (ie, herpes viral DNA synthesis/replication is selectively inhibited)

Monitoring Parameters

Dietary Considerations

Patient Education

Inform prescriber of all prescriptions, OTC medications, or herbal products you are taking, and any allergies you have. Take for prescribed length of time, even if condition improves. Do not discontinue without consulting prescriber. This is not a cure for genital herpes. May cause mild GI disturbances (eg, nausea, vomiting, constipation, diarrhea), fatigue, headache, or muscle aches and pains. If these are severe, contact prescriber. Breast-feeding precaution: Do not breast-feed.